#include <psemek/ecs/entity_container.hpp>

namespace psemek::ecs
{

	bool entity_container::alive(entity_handle const & entity) const
	{
		return entity_list_.get_entities()[entity.id].epoch == entity.epoch;
	}

	void entity_container::destroy(entity_handle const & entity)
	{
		auto entities = entity_list_.get_entities();
		auto & data = entities[entity.id];
		auto & iteration_data = data.table->get_iteration_data();

		if (!iteration_data || iteration_data->current_row < data.row)
		{
			remove_row(*data.table, data.row, entities);
			entity_list_.destroy(entity.id);
		}
		else
		{
			data.table->push_remove(data.row);
			entity_list_.destroy(entity.id);
		}
	}

	entity_accessor entity_container::get(entity_handle const & entity)
	{
		auto const & data = entity_list_.get_entities()[entity.id];
		return {data.table, data.row};
	}

	void entity_container::remove_row(detail::table & table, std::uint32_t row, util::span<detail::entity_data> entities)
	{
		// Swap with the last row in that table
		auto table_entity_handles = table.get_entity_handles();
		table.swap_rows(row, table_entity_handles.size() - 1);
		table.pop_row();
		auto swap_handle = table_entity_handles[row];
		entities[swap_handle.id].row = row;
	}

}